Four year old babies with cough and phlegm can be given oral medicine for symptomatic treatment, such as Feili Cough Mixture, Ambroxol Oral Liquid, and Xiaoer Zhike Huatan Granule. They can also be given aerosol inhalation for cough and phlegm treatment. The commonly used drug is budesonide suspension. If the baby coughs with sputum, the sputum is white, indicating that it is caused by virus infection, you can take appropriate antiviral drugs for treatment, such as Pudilan anti-inflammatory oral liquid. If the cough sputum is yellow, indicating that there is bacterial infection, antibiotics can be properly used for anti infection treatment, such as cefaclor dry suspension.